BOSTON - State Rep. George Peterson (R-Grafton) announced on Monday that he will not seek re-election in November, bringing an end to 20 years in office.

Peterson, the house assistant minority leader, represents the towns of Grafton, Northbridge and Upton. He said he believed it was time to move on.

"I've had 20 great years up here," he said. "I have my health and my family, and I think it's time to move on to the next phase of my life."

That "next phase," he said, certainly wouldn't be lacking in activities.

"I've got seven grandkids, so I'll be spending more time with them," he said. "We'll be getting a (recreational vehicle) and traveling around the country - the Grand Canyon, some national parks."

He said he also looked forward to doing work around the house, hunting, fishing and golfing.

Peterson said he was proud of his wide range of accomplishments, but wasn't sure which he could call his biggest.

"I'll let other people define my legacy," he said. "We've done a lot of good things, from fighting to continue local funding to trying to be more open and accessible to my constituents."

Peterson expressed his confidence in the state Republican party and believes Republicans can be elected in Massachusetts.

"When I first came up in 1995, there were 34 to 35 Republicans in the house," he said. "I've seen seen it go down to 15, but it's back on the upswing. I believe it will be a very good year for Republicans - I believe there will be more Republicans in the House than when I came in."

Peterson said he would be supporting a candidate to succeed him, but declined to name that person.

State Sen. Richard Moore (D-Uxbridge) praised Peterson's efforts.

"Throughout his tenure in office, George has not only been a tireless advocate for the constituents and communities he represents, but built strong relationships on both sides of the aisle to effect positive changes and progress," he said in a statement.

House Minority Leader Bradley Jones (R-North Reading) said he was sad to hear of the decision.

"For the past two decades, George has been a great colleague, an invaluable member of my leadership team and a cherished friend," he said in a statement. "A zealous advocate of the outdoors and a champion of Second Amendment rights, (he) truly embodies what it means to be a public servant."

Peterson said it would be "really tough" to say goodbye to his colleagues.